Hydroelectric installation



June 19, 1928. 1,674,609

A. PFAU HYDROELECTRI C I NS TALLATION Filed Sept. 24, 1924 Patented June 19, 1928.

UNITED STATES PATENT OFFICE.

ARNOLD PI'AU, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO ALLIS-CHALMERS MANU- 'I'ACTUBING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF DELA- WARE.

HYDROELECTRIC INSTALLATION.

Application filed September 24, 1924. Serial No. 739,476.

This invention relates in general to power installations, and itrhas particular relation to hydro-electric'power installations where the hydraulic machine is operative under or,

against a widely varying head.

Turbines of hydraulic power plants which are subject to a highly variable head such, for instance, as certain inland streams or the hi 'h and low tide of the ocean, suffer a considerable loss in the power develo ed. This is particularly the case with very ow heads where even a slight change in the head amounts to quite a considerable portion of the full normal ,head. For instance, if the normal net head is 4.5 meters, the highest head 6 meters, and the lowest head two meters, the total average amounts to 4 meters or 88.8% of the normal head.

It is well known that the number of revolutions or speed of a turbine varies with the square root of the net head. For instance,

if the revolutions are 100 per minute on the 16 meters head, it is 100 divided by /5; or about 71 revolutions under 8 meters, and it is 100 divided by {4 or revolutions, that is half of the former amount when the head has dropped to of the maximum head.

If a turbine is directly connected to an alternating current generator, it should always operate at the same number of revolutions, otherwise the number of periods or frequency of the current would change, and this would render parallel operation with other generators impossible. Therefore, if a turbine were normally designed for 100 revolutions under 16 meters net head, it would have to develop under 4 meters head, not 50 revolutions, but twice as much, that is, 100 revolutions, in order to roduce. current of the proper number of periods or frequency. A turbine operating at a speed which is 100 per cent higher than normal, however, shows such unfavorable hydraulic efficiencies that it becomes uncomniercial to still use a turbine for such operating conditions.

The speed of the generator could be maintained normal by using in steps belt drives or similar devices with proper transmission ratios. This arrangement, however, is impossible where large units are used and particularly when the turbine and generator are directly coupled, which is the most favorable mechanical solution.

The powerdeveloped by the turbine is even more sensitively affected by a change n the net head; first, on acount of the head 1tself, second, on account of the discharge capaclty. It is well known that Q1 :.Q2 1 i/E, where Q,=quant ity of water under the head H Q =quant1ty of water under the head H a vformulae, only 500 H. P. under 4 meters,

and this does not as yet consider the loss of power due to reduced efficiency. Now, if the turbine must maintain its 100 revolutions, it would have to run twice as fast as is necessary in order to maintain its'normal elliciency. Therefore, the efliciency will drop to such extent that nothing will be left of the 500 H. P. In other words, the turbine will produce no power and, therefore, represents a dead capital investment.

For medium or high variable heads or, in general, for conditions which permit of the use of horizontal shaft units, the roblem of the economical utilization of bee can be solved by arranging the hydraulic parts in 96 two separate h draulic elements, one located on each side 0 the generator. The Francis turbine which applicant has disclosed in United States Patent No. 1,023,585, dated April 16, 1912, and which is a double over- 100 hung Francis turbine, can be employed in such a manner that one side utilizes the high head and the opposite side utilizes the low head. In this case, the absolute number of revolutions of the two turbine sides are naturally the same, where as the individual capacities of the turbines are selected in accordance with the corresponding heads and quantities of water required to suit the capacity of the generator.

The constructions for which patent is herewith applied, provide a suitable solution of the problem, inasmuch as there are employed, not two different turbines, but rather two different dynamo-electric machines, such as generators, or a single machine having characteristics such as are ordinarily possessed by two separate machines.

The present application is a continuation in part of applicants copending application Ser. No. 498,720, filed Sept. 6, 1921, the claims of the latter application bein concerned with general features of the cation being more directly concerned with the automatic control of the installation, more particularly through speed regulation of the turbine of the installation.

As a feature of this invention, there is disclosed a special speed governor arrangement, the apparatus being adapted to regulate the turbine so as to maintain the speed thereof constant at a plurality of different selected values required to insure the pr0- duction of electrical energy of the desired constant frequency when the dynamo-electric machine unit is operating as a generator. As a further feature, the control of the hydro-electric system, as to the necessary changes or operations to accommodate for difference in the head on the turbine or other variable characteristic, is rendered automatic in response to an operating condition, such as a change in effective ead or pressure on the hydraulic turbine.

It is an object of this invention to provide the above described and other related improvements in hydro-electric systems, all as will be apparent from the drawings and description relative thereto, disclosing an embodiment of this invention, and as will be more particularly apparent from the claims herein.

In the accompanying drawings:

Fig. 1 is a diagrammatic showing of a hydro-electric system embod ing features of this invention, parts of t e hydro-electric installation being shown/ in section.

Fig. 2 is a schematic showing of a feature of operation of the speed controlling governor forming part of the system of Fig. 1.

In accordance with the disclosure of the drawings, the turbine A is directly coupled with the electric generator unit B. made u of the generator elements B, and B,,, an

hydro electric installation, and the present applithe exciter C. All rotating parts of this unit are carried on the thrust bearing D. The turbine may be automaticall controlled by a governor acting on the regu ating shaft E, as will be described hereinafter.

The generator B consists of a rotor fixed on the main shaft and having two sets of poles B, and B. so arranged that the set B, produces the required number of periods or frequency 1) at a speed n and a number of poles w, and. the other set B produces the same number of riods p at a speed n and m poles. Sim1larl two separate stator elements S, and b, are provided, corresponding to the two sets of poles B, and B,, respectively, the field element B, and the stator S, constitutin the nerator B and the field element 2 an its stator S constituting the generator B The exciter fl is so dimensioned that it furnishes current for either one of the two alternator sets.

The generator B, is connected, through a circuit 4 and a switch 5, when in its upper closed osition, to a circuit 6; and the generator b is connected through a circuit 7 and the switch 5, when in its lower closed position, to the circuit 6. The circuit 6 is connected, permanently or through a circuit opening switch, to the line circuit 8. The switch 5 is preferably biased to a neutral open position, as b a spring 9, and is positively actuated to th its upper and lower closed positions in a manner as will be described hereinafter, so as to connect the generators B, and B respectively, to the line circuit 8.

Let us now assume that the turbine is to utilize any;head between the limits H and H Assuming now that this head is divided in two heads h and h, in such a wa that It varies between the limits H, a maximum, and H a minimum, and It varies between the limits H,,,, a maximum, and H,

a minimum. For each of these two heads, h and h, the most favorable speed it and n of the turbine is so selected that the desired uniform frequency p is obtained with the correspondin even number of poles. For instance, if t e best speed of the turbine for head It be 150 and for head 12. be 120, then pole set B, has 40 poles and the other pole set B has 50 poles, if current of a frequency of 50 cycles per second is required.

Under the low head h, the turbine naturall develops less power at full gate than it oes under the igh head h, therefore, generator B, can be designed for a correspondingly smaller capacity in order to operate at best efiiciency.

The speed of the whole unit AB(}D can be held within desirable limits by an automatic governor of known construction. One method for controlling the two s ds n and n can be seen from Figures 1 an 2 and can be accomplished in the manner described hereinbelow.

The drawing shows schematically a servomotor M of well known construction, such as is used for controlling the guide-vane openings of turbines. The regulating valve V receives fluid presure, as indicated at K, and admits same, according to the position of the regulating valve piston V either to a passage K communicating with the front side of the regulating piston M of the servo-motor M, or to a passage K communicating with the rear side of the regulating iston M The desired actuation of the turbine guide vanes or other controlling means for the turbine A is transmitted from the regulating pistoIfM of the servo-motor M in any suitable well-known manner. For convenience, a rod may be provided at the rear side of the piston and passing through a sealed aperture in the rear end Wall of the cylinder, this rod being connected through a rod or link M to an operating arm E on the regulating shaft E. The motion of the regulating piston M, is transmitted to a relay R. A speed governor P receives its revolutions through a drive T from the turbine shaft and transmits the motion of the shifting collar or stud of the governor to the floating lever VP-R. As soon as the regulating valve piston V is raised out of its mid position, fluid pressure K reaches the front side K of the regulating piston M,, moving the latter until the regulating valve piston V is brought back to its former mid position. This is attained by the relay R and the floating lever RP-V in such a wa that the forward motion of the regulating piston M produces an upward motion of the end R of the floating lever, causing the regulating valve piston V to be lowered after it had first been raised by the speed governor.

The corresponding strokes of the collar of the speed governor P produce strokes f and f on the relay in the following proportion:

where f and f are strokes of the relay R cor; responding to strokes a and a, respectively, of the collar of the speed governor P, and AI -V) is the length of that portion of the oating lever between the speed governor P and the regulating valve V, and (RP-V) is the total length of the floating lever between the relay R and the regulating valve V.

To each position of the collar there corresponds a certain number of revolutions or speed of the speed governor, 1f the design of the latter is static. If we assume that the revolutions or speed corresponding to the highest position of the speed governor is is conventionally termed the total degree of speed variation of the speed governor; and the values and where d is the degree of speed variation between speeds at, and

7b,, or corresponding positions of the governor collar, and

d is the degree of variation between speeds n, and n,, or corresponding positions of the governor collar. I

These values cl and d then indicate the correspondin degrees of speed variation of the part stro (es of the collar of the speed governor, or of correspondin relay strokes f and f. \Vith reference to t 1e function of the servo-motor M, f and f are generally termed active strokes of. the speed governor, that is, the strokes necessary for producing the total stroke of the regulating piston 711,.

By shifting the hand wheel R along the relay rod R, in upward or downward direction these active relay strokes f and f can be distributed at will over the whole stroke F, Figure 2. From this, it follows that the speeds n and n, or the mid positions of the corresponding active strokes of the speed governor, as indicated in Figure 2, are such that these corresponding mid positions are located Within the total stroke of the speed governor produced b the speeds a and n and this consequent v controls the corresponding speeds of the turbine.

' If the total stroke of the collar of the speed governor is selected large, as also the corresponding difference in the s eeds n and n that is, the corresponding egree of variation of the speed governor is fore, regulate around the mid position of the relay.

For example: assume that d,,=40%, d'=d==6%, n=150, and n'=120: then n =135 and from formula (3), we obtain n =154.5, and n,=145.5, from formula (2),

ill)

we obtain n,'=123.6, and n,=116.4, from formula (1), we obtain n,=162, and n,,=108. The spaces 1, 2, 3 and 4, indicated in Figure 2, therefore, correspond to difl'erences in numbers of revolutions of 7.5, 10.5, 11.4, and 8.4, respectively, and therefore still permit a substantial variation of both regions of speed a and n in upward and downward direction.

WVith this arran ement, therefore, we can obtain the result t at both operating speeds n and n can be controlled with the same drive of speed governor and with the same speed governor. To insure this result, means are provided for adjusting the position of the end R of the lever VP-R on the relay rod R,, a hand or otherwise adjustable wheel R being the specific means shown for securing the desired result.

The springs of the governor are of such strength as to produce the desired governing effect through a wide active range, to thereby obtain a regulating effect that produces a plurality of constant s eeds of the turbine, these speeds corr onding to different settings of the adjusting wheel B on the rod R This desired regulation is such that the full stroke of the regulating or com nsating mechanism, such as the valve 1 of the servo-motor, corresponding to the full stroke f, f in either direction from such normal speeds, corresponds to only partial stroke of the governor fly ball device, the effect being such as to produce constant speed independently of a variation in the load of the turbine between substantially no load and the desired limit of overload; and further, this desired regulation to produce constant speed at variable load is obtainable for any one of widely variant operating speeds, such as might correspond to operation of the turbine under conditions of variable head.

It may tion B.B,,C can be so arranged that A serves as a ump instead of a turbine in which case I5. and B serve as two corresponding motors instead of generators in such a way that the fact that the electrical part B."B has two different operating speeds permits operation of the pump to produce two different lifts.

It may furthermore be remarked that the turbine A and the generator elements B,-B of such a unit could be so built that A acts as a turbine, first rotating in a given direction and delivering electrical energy with one of the two generators B, or B, transforming such energy, under the speed nor a, respectively into electric energy of the constant number of periods of frequency 1), or that the turbine A rotates in a direction opposite to the former and operat es as a pump absorbing energy which 15 furnished by the motors ,--B formerly operating also be remarked thata combinaas generators, the energy supplied to the motors being at the common frequency but the motors operating at the difierentspeeds n and n respectively. is

In certain installations where the variation in head occurs relatively often or at a relatively rapid rate it may be desirable that the adjusting wheel R be automatically shiftable to its several positions on the rod R corresponding to the several desired operatings eeds. This desired operation of the end of the lever VP-R may be secured by means of electro-magnets or a motor, preferably a reversible one, acting to shift the position of the adjusting wheel as the head on the turbine varies orvpasses predetermined limiting values. One desirable method of securing the desired result might be to provide floats in the head water and tail water with such a mechanical or electrical connection therebetween as would produce a resultant difi'erential movement corresponding to the difference in level between head water and tail water, this differentially movable element being operable to close contacts of a reversible motor as the difference in level reaches predetermined values corresponding to the average net head for the different operating speeds. There may be provided an automatic cutout or other device that renders the motor inoperative when the adjusting wheel R has been shifted to the desired position and the desired change in connections between the consumption circuit and the generators has been made.

The particular embodiment of this feature of automatic control selected for specific illustration. and description herein includes the provision of a float 12 in the head water of the turbine and a float 13 in the tail water of the turbine, with flexible cords or chains connected to each of these floats and suitably uided and passing over pulleys fixed to ]&Ck shafts 14,15, respectively, of a me-' chanical differential, the floats 12 and 13 being balanced by suitable weights 16 and 17, respectively, connected to the other end of the flexible cords attached to the floats. The mechanical differential gear including the jack shafts 14 and 15, has as its differentially driven element a gear 18 which actuates a geared segment 19 connected to an indicating needle 21 which moves over a scale to give an exact indication of the difference in level between the floats 12 and 13, and hence, the net efl'ective head on the turbine A.

The segment 19 or the indicating needle 21 carries an operating arm 23 having a loose connection with the movable switch arm 24, preferably of the spring, sna -operated type, which in its lower position 0 oses the c rcuit through contact 25, as indicated, and n its upper position is adapted to close a circuit through contact 26. The circuits through the switch 24 and the contacts 25 and 26, are supplied from a direct current supply line 27. When the switch 24 is in the position indicated, a circuit is closed through the contact 25 and an energizing winding 28 of an electro-magnetically actuated switch 29, and through an energizing winding 30 of a switch to be described hereinafter. When the switch 24 is in the position 26, it closes a circuitthrough an energizing winding 31 of an electro-magnetically actuated switch 32 and also through an energizing winding 34 of an electro-magnet'ically operated switch to be described hereinafter. A switch 36, either manually or automatically operated, in connection with the switch 29 controls a circuit through the energizing winding 37 of an operating electro-magnet for the switch 5; and a switch 39, manually or automatically operated, in connection with the switch 32 controls an energizing winding 38 of a second operating electro-magnet for the switch 5. The movable switch arms 36 and 39 are provided with stops for cooperation with latches or hooks 40 mounted on the stems of or otherwise mechanically associated with the switches 29 and 32, so as to provide for the positive actuation of the switch 36 to open position when the switch 29 is moved to open position and for similar actuation to open position of the switch 39 when the switch 32 is moved to open position.

A movable bridging switch member 41' is connected to the movable part of the electro-magnet energized by the winding 30 so as to provide for actuation of this switch member by the electro-m et, this switch member closing a circuit t rough the contacts 42 in one operative position, and through the contacts 43 in another operative position. A second movable bridging switch member 45 is mechanically associated with the electro-magnet energized by the winding 34 and is operative to close a circuit through the switch contacts 46 in one operative position and to close a circuit through the contacts 47 in another operative position. As indicated, the operating stems or rods of the electro-magnetically actuated switches 41 and 45 are mechanically connected. so as to provide for simultaneous operation, the switch 41 closing a circuit through contacts 42 and the switch 45 closing a circuit through contacts 46, when the device is in one operative position, and the switch 41 closing the circuit through contacts 43 and the switch 45 closing a circuit through contacts 47, when the device is in the second operative position. The contacts 42, 43, 44 and 45 are located in the supply circuit of a motor 51 and provide for forward and reverse operation of this motor. A pinion 52 is provided on the motor shaft, the same being engageable with a gear 53 attached to the adjusting wheel R, on the relay rod R,. In the motor circuitthrough the switch 42 is located a switch 56 biased to closed position and operable to open position by an electro-magnet having an energizing winding 57; and in the motor circuit through contacts 43, there is disposed a switch 58 biased to closed position and operable to open position by an electro-magnet having an energizing winding 59. The circuit of the energizing winding 57 is completcd through a switch element 61, and a switch element 62; and the energizing winding 59 is completed through a switch 63 and a switch 64.

A portion of the adjusting wheel R, is provided with a projection or flange 67 adapted to actuate the switches 61 and 63 to closed position, these switches being as sumed to be biased to open position. However, this operating means may include a loose connection or portion between the element 67 and the several switches, which insures positive operation of these switches to both open and closed position; and these switches 61 and 63 may be of the snap-operated type. The referable means ior connecting the end 0 the lever VP--R to the adjusting wheel R includes a sleeve 68 held between flanges on the rotatable adjusting wheel proper, this sleeve being held against rotation in any suitable manner and having the end of the lever connecting to this nonrotatable sleeve. The switch-actuating projection 67 is preferably mounted on the sleeve 68.

When the hydraulic turbine Ais operatingunder its higher head H, the adjusting wheel R is in the position indicated, with the switch 61 in closed position and the fulcrum of the lever V F-R at the point to maintain the desired predetermined speed, thenet effective head on the turbine being shown by the indicating needle 21 of the differential level indicator. With the dynamo-electric unit operating as a generator the generator element B, supplies energy of the desired frequency to the line circuit 8, through the switch 5. The other several parts of the system are in the positions indicated, with the circuit of the motor 53 open at the switch 56, and the switch 5 held in its upper closed position through energization of the winding 37 of its operating electromagnet. The speed of the unit is regplated un er conditions of variable load, y the governor P and its servo-motor acting upon the guide vanes of the turbine.

As the net efi'ective head on the turbine A drops to a predetermined point, the indicating needle 21 is shifted and as it reaches a predetermined head indication, the switch 24 is shifted to open the circuit through the contact 25 and to close the circuit through the contact 26. Opening of the circuit through the contact 25 causes de-energization ofthe windings 28 and 30, with a consequent opening of the switches 29 and 36 and consequent de-energization of the winding 37 and shifting of the switch 5 to its neutral'open position. Opening of the switch 29 causes opening of the switch 62 and closure of the switch 64, because of the mechanical connection between the switch 29 and the other two switches. Closure of the circuit contact 26 causes energization of the winding 31 and closure of the switch 32, and energization of the windin 34, with consequent opening of the circuit through contacts 42 and 46 and closure of the circuit through the contacts 43 and 47, thus completing the operating circuit of the motor 51, through the switch 58.

Operation of the motor 51 causes shifting of the adjusting wheel R which carries the pivotal support for one end of the lever V--l-R down along the relay rod 11,, the operating element 67 permitting opening of the switch 61 with consequent de-energization of the winding 57 and closure of the switch 56, and this element 67 finally causes closure of the switch 63, thus completing the.circuit through the energizing winding 59 and causing opening of the switch 58 in the motor circuit, with consequent stoppage of the motor 51. It will be ap arent that a suitable braking device may a supplied to cause actual stoppage of the motor within an desired or predetermined interval.

ith the adjusting wheel R in its new position corresponding to the lower speed at which it is desired to maintain the turbine A, the switch 39 may be closed manually, or automatically through the circuit which is completed by closure of switch 63, closure of the latter switch causing energization of the winding 75 of an electromagnet whose core or armature is mechanically connected to the switch 39 and, on energization of the magnet, draws the switch into closed position, thus causing actuation of the switch 5 to its lower operative position wherein it connects the generator B to the supply line 8. Under ordinary conditions, the turbine A will probably have assumed its new operating speed during shifting of the adjusting wheel R This new speed of the turbine is maintained by the governor P, with the new setting of the adjusting wheel R and the servo-motoroperating upon the ide vanes of the turbine.

It will be apparent that during the further operation of the installation, as the head on the turbine increases again to the upper predetermined value, the switch 24 will be again shifted to open the circuit through the contact 26 and close the circuit through the contact 25, this action causing operation of the various switches to the positions indicated in the drawing, and the adjusting wheel R to its upper position, as indicated, wherein the governor is again efl'ective to maintain the higher operating speed of the turbine.

With this arrangement for thus var ing features of the operation of the tur ine, such as the speed and, hence, the amount of water used per horsepower developed, as may be required or determined by variations in the available supply of water at the turbine inlet, the available water supply is economically and efiiciently used; and the capital investment involved in the installation is made to pay an increased return.

While the hydro-electric unit described above finds great utility when connected with a distribution circuit whose frequency is definitely established by means other than said unit, nevertheless, it finds considerable utility when it is the only power unit connected to or establishing the frequency-of the distribution circuit, for through the means described for maintaining a plurality of definite or predetermined operatin w speeds for the generating element, the unit 1 readily operative to furnish electrical power to such distribution circuit at the desired definite operating frequency.

It should be understood that the invention claimed is not limited to the exact details of construction and design or the embodiment or use shown or described herein, for various modifications and other embodiments and uses of the invention will be apparent to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

1. A h dro-electric unit for operation under con itions of variable effective head, comprising a hydraulic turbine operative at different normal speeds dependent upon the effective head, an alternating current electrical generating unit operatively connectible to said turbine to be driven thereby and adapted to produce alternating current of a predetermined frequency when driven by said turbine operating at said difi'erent speeds, and controlling means responsive to variations in the effective head on said turbine and operative to insure operation of said turbine at anv one of said speeds determined by the effective head on said tur- 2. A h dro-electric unit for operation under con itions of variable effective h'ead, comprising a hydraulic turbine operative at difi'erent normal speeds dependent upon the effective head, an alternating current electrical generating unit operatively connectible to said turbine to be driven thereby, a regulating device operatively associated with said turbine for controlling the frequency of the electrical energy supplied by said generating unit when driven by said turbine, and means.

automatically responsive to the energy avail able at the turbine inlet for controlling said regulating device. a

In combination, a hydro-electric unit comprising a hydraulic turbine subject to operation under widely varying fluid heads, an alternating current generating unit arranged to be driven by said turbine, and governing means including instrumentalities responsive to a condition attendant upon the operation of said unit for insuring operation of said unit at a lumlity of controlled speeds throughout said range of variation of said head.

4. In an electrical power system, a prime mover, an alternating" current generating unit driven thereby, means for regulating the admission of operating fluid to said prime mover, means for controlling said regulating means to insure operation of said eneratin unit at a predetermined speed un er norma running conditions, and means automatically responsive to a conditionattendant upon the operation of said prime mover for causing said controllin means to insure controlled operation of said generating unit at a speed other than said predetermined speed.

5. In an electrical power system, a hy draulic turbine, an alternating current generator unit driven thereby, means for regulating the admission of water to said turbine, speed responsive governing means for controlling the speed of said turbine to insure operation thereof at one predetermined speed under normal running conditions, and floatcontrolled means responsive to the effective head on said turbine for adjusting said governing means to cause the latter to insure controlled operation of said turbine at a different speed.

6. A hydro-electric installation, comprising a hydraulic turbine subject to a variable available supply of water, an alternating current generating unit driven by said turbine, controlling means for said turbine operative to maintain a predetermined speed and frequency of said generating unit under conditions of variable load thereon, and means responsive to variations in the available supply of water for said turbine for exercising a controlling efl'ect thereon during operation for power supplying purposes and independently of the load thereon.

7 A hydro-electric installation, comprising a h draulic turbine subject to a variable available supply of water, an alternating current generator connected to be driven by saidturbine, and means independent of the load on said turbine and responsive to a characteristic of the available supply of Water for said turbine for determining the maximum power that may be converted by said turbine during controlled operation thereof.

8. A hydro-electric unit, comprising a hydraulic turbine operable at different speeds, an alternating current generating unit operatively connectible to said turbine to be drlven thereby, means for automatically controlling the speed of said turbine to insure the maintenance of a predetermined substantially constant speed thereof, and means responsive to an operating characteristic of said turbine for adjusting said speed controlling means to insure operation of said turbine under other automatically controlled conditions.

9. A hydro-electric unit, comprising a hydraulic turbine, an alternating current generating unit operatively connectible to said turbine to be driven thereby, means for controlling the operation of said turbine, and float-controlled and electromagnetically actuated means for adjusting said controlling means during operation of said turbine to vary a characteristic of such operation.

10. A hydro-electric unit, comprising a hydraulic turbine, an alternating current generating unit operatively connectible to said turbine to be driven thereby, means for automatically governing said turbine to insure its operation at a controlled speed, and means responsive to a condition attendant upon the operation of said turbine for automatically adjusting said governingmeans during operation of said turbine to vary a characteristic of such operation.

11. A hydro-electric unit, comprising a hydraulic turbine operable at different speeds, an alternating current generating unit 0 eratively connectible to said turbine to be riven thereby, means for controlling the speed of said turbine, and means including a remote controlled electric motor Whose operation is automatically responsive to a condition attendant upon the operation of said turbine for adjusting said controlling means to insure operation of said turbine at either one of a plurality of constant speeds.

12. A hydro-electric unit, comprising a hydraulic turbine operable at different speeds, an alternating current generating unit operatively connectible to said turbine to be driven thereby, means comprising a speed controlled governor including a pivoted element for regulating the supply of 'water to said turbine, and means including a reversible motor operatively responsive to variations in an operating characteristic of said turbine and effective to ad'ust a fulcrum of said pivoted element 0 said governor to thereby insure the capability of operation of said turbine at a plurality of different constant speeds.

13. A hydro-electric unit, for operation under variable speed conditions, comprising a hydraulic turbine operable under variable head conditions, an alternating current generating un-it operatively connectible to said turbine to be driven thereby, a speed controlled governor including a pivoted element for regulating the supply of water to said turbine, and means operativel responsive to the effective head on said tur i-ne and effective to adjust a fulcrum of said ivoted element of said governor to insure t at the latter is capable of maintaining difierent constant speeds of operationof said turbine.

14. A hydro-electric installation, comprisin an alternating current distribution circuit, a hydraulic turbine adapted to operate under conditions of widely varying head, and an alternating current generating unit adapted to be driven by said turbine and to supply said circuit through variable electrical connections, means for governing the speed of said turbine to insure its operation at any one of a plurality of predetermined speeds, and means automatically responsive to the effective head on said turbine for adjusting said governing means and said variable connections to insure controlled operation of said unit at different speeds and the appropriate connection of said generating unit to said circuit to cause said generating unit to supply electrical energy to said circuit at a predetermined frequency independently of the particular controlled speed of operation of said turbine.

15. A hydro-electric installation for operation under conditions of Widely varying head, comprising a hydraulic machine operable at a plurality of different normal speeds, an alternating current dynamo-electric machine operatively connected to said hydraulic machine for operation therewith at said different normal speeds, a distribution circuit connectible to said dynamo-electric machine and carrying current whose frequency is established by means other than said dynamo-electric machine, and instrumentalities automatically controlled in response to a characteristic of the head to which said bydraulic machine is subjected for insuring the transfer between said distribution circuit and said dynamo-electric machine of energy operation of said turbine for maintaining the frequency of the current supplied by said generator unit substantially constant independently of the particular one of said speeds at which said generating unit is driven.

17. A hydro-electric installation for operation under conditions of widely varying head, comprising an alternating current generating unit, a turbine mechanically connected to said generatin unit and operable to drive said unit at a p urality of predetermined speeds de endent upon the head on said turbine, an alternating current distribution circuit connectible to said generating unit and means automatically controlled in response to a characteristic of the head on said turbine for determining the particular one of said speeds at which said generating unit is driven and maintaining said generating unit in operation at any one of said particular speeds to enable said unit to furnish current of a predetermined frequency to said distribution circuit independently of which of said speeds is possessed by said gen erating unit at any time.

18. A power installation for operation under conditions of widely varying speed of prime mover, comprising an a ternati-ng current generating unit, a prime mover operable to drive portions of said generating unit at a plura ity of widely varying speeds, and means automatically operative in response to a condition affecting the operation of said prime mover for insurin that the frequency of the energy supplied 51y said generating unit is substantially constant in spite of said operation at said different speeds of said prime mover.

19. A hydro-electric installation for operation under conditions of widely varying turbine speed, comprising an alternatin current generating unit, a turbine opera 10 to drive said generating unit at widely different speeds, and means for causing the frequency of the energy supplied by said generating unit to be substantially constant in spite of operation of said turbine at said different speeds, said means being responsive to a condition attendant upon the supply of hydraulic energy available for conversion by said turbine.

' In testimon whereof, the signature of the inventor is a xed hereto.

ARNOLD PF AU. 

